Bug 1404181 - Part 23: Only rebuild items within a displayport when the displayport changes, rather than rebuilding the whole document. r=mstange

MozReview-Commit-ID: IYEPCKSvtBY

--HG--
extra : rebase_source : f6b65a88dcd82b7828af371874bf3adde2af688f

dom/base/nsDOMWindowUtils.cpp

@@ -474,6 +474,9 @@ nsDOMWindowUtils::SetDisplayPortForElement(float aXPx, float aYPx,
     }
   }
 
+  nsLayoutUtils::InvalidateForDisplayPortChange(content, !!currentData,
+    currentData ? currentData->mRect : nsRect(), displayport);
+
   nsIFrame* rootFrame = presShell->FrameManager()->GetRootFrame();
   if (rootFrame) {
     rootFrame->SchedulePaint();

layout/base/nsLayoutUtils.cpp

@@ -1375,6 +1375,54 @@ nsLayoutUtils::GetDisplayPortForVisibilityTesting(
   return usingDisplayPort;
 }
 
+void
+nsLayoutUtils::InvalidateForDisplayPortChange(nsIContent* aContent,
+                                              bool aHadDisplayPort,
+                                              const nsRect& aOldDisplayPort,
+                                              const nsRect& aNewDisplayPort,
+                                              RepaintMode aRepaintMode)
+{
+  if (aRepaintMode != RepaintMode::Repaint) {
+    return;
+  }
+
+  bool changed = !aHadDisplayPort ||
+        !aOldDisplayPort.IsEqualEdges(aNewDisplayPort);
+
+  nsIFrame* frame = GetScrollFrameFromContent(aContent);
+  if (frame) {
+    frame = do_QueryFrame(frame->GetScrollTargetFrame());
+  }
+
+  if (changed && frame) {
+    // It is important to call SchedulePaint on the same frame that we set the dirty
+    // rect properties on so we can find the frame later to remove the properties.
+    frame->SchedulePaint();
+
+    nsIFrame* displayRoot = nsLayoutUtils::GetDisplayRootFrame(frame);
+    RetainedDisplayListBuilder* retainedBuilder =
+      displayRoot->GetProperty(RetainedDisplayListBuilder::Cached());
+    if (retainedBuilder) {
+      nsRect* rect =
+        frame->GetProperty(nsDisplayListBuilder::DisplayListBuildingDisplayPortRect());
+      if (!rect) {
+        rect = new nsRect();
+        frame->SetProperty(nsDisplayListBuilder::DisplayListBuildingDisplayPortRect(), rect);
+        frame->SetHasOverrideDirtyRegion(true);
+      }
+      if (aHadDisplayPort) {
+        // We only need to build a display list for any new areas added
+        nsRegion newRegion(aNewDisplayPort);
+        newRegion.SubOut(aOldDisplayPort);
+        rect->UnionRect(*rect, newRegion.GetBounds());
+      } else {
+        rect->UnionRect(*rect, aNewDisplayPort);
+      }
+    }
+  }
+
+}
+
 bool
 nsLayoutUtils::SetDisplayPortMargins(nsIContent* aContent,
                                      nsIPresShell* aPresShell,
@@ -1403,9 +1451,6 @@ nsLayoutUtils::SetDisplayPortMargins(nsIContent* aContent,
   DebugOnly<bool> hasDisplayPort = GetHighResolutionDisplayPort(aContent, &newDisplayPort);
   MOZ_ASSERT(hasDisplayPort);
 
-  bool changed = !hadDisplayPort ||
-        !oldDisplayPort.IsEqualEdges(newDisplayPort);
-
   if (gfxPrefs::LayoutUseContainersForRootFrames()) {
     nsIFrame* rootScrollFrame = aPresShell->GetRootScrollFrame();
     if (rootScrollFrame &&
@@ -1419,12 +1464,8 @@ nsLayoutUtils::SetDisplayPortMargins(nsIContent* aContent,
     }
   }
 
-  if (changed && aRepaintMode == RepaintMode::Repaint) {
-    nsIFrame* frame = aContent->GetPrimaryFrame();
-    if (frame) {
-      frame->SchedulePaint();
-    }
-  }
+  InvalidateForDisplayPortChange(aContent, hadDisplayPort, oldDisplayPort,
+    newDisplayPort, aRepaintMode);
 
   nsIFrame* frame = GetScrollFrameFromContent(aContent);
   nsIScrollableFrame* scrollableFrame = frame ? frame->GetScrollTargetFrame() : nullptr;
@@ -3723,7 +3764,7 @@ nsLayoutUtils::PaintFrame(gfxContext* aRenderingContext, nsIFrame* aFrame,
     MaybeCreateDisplayPortInFirstScrollFrameEncountered(aFrame, builder);
   }
 
-  nsRect dirtyRect = visibleRegion.GetBounds();
+  nsRect visibleRect = visibleRegion.GetBounds();
 
   {
     AUTO_PROFILER_LABEL("nsLayoutUtils::PaintFrame:BuildDisplayList",
@@ -3760,7 +3801,7 @@ nsLayoutUtils::PaintFrame(gfxContext* aRenderingContext, nsIFrame* aFrame,
 
       nsDisplayListBuilder::AutoCurrentScrollParentIdSetter idSetter(&builder, id);
 
-      builder.SetVisibleRect(dirtyRect);
+      builder.SetVisibleRect(visibleRect);
       builder.SetIsBuilding(true);
 
       const bool paintedPreviously =
@@ -3777,7 +3818,7 @@ nsLayoutUtils::PaintFrame(gfxContext* aRenderingContext, nsIFrame* aFrame,
       if (!merged) {
         list.DeleteAll(&builder);
         builder.EnterPresShell(aFrame);
-        builder.SetDirtyRect(dirtyRect);
+        builder.SetDirtyRect(visibleRect);
         builder.ClearWindowDraggingRegion();
         aFrame->BuildDisplayListForStackingContext(&builder, &list);
         AddExtraBackgroundItems(builder, list, aFrame, canvasArea, visibleRegion, aBackstop);
@@ -3838,7 +3879,7 @@ nsLayoutUtils::PaintFrame(gfxContext* aRenderingContext, nsIFrame* aFrame,
     }
 #endif
     *ss << nsPrintfCString("Painting --- before optimization (dirty %d,%d,%d,%d):\n",
-            dirtyRect.x, dirtyRect.y, dirtyRect.width, dirtyRect.height).get();
+            visibleRect.x, visibleRect.y, visibleRect.width, visibleRect.height).get();
     nsFrame::PrintDisplayList(&builder, list, *ss, gfxEnv::DumpPaintToFile());
 
     if (gfxEnv::DumpPaint() || gfxEnv::DumpPaintItems()) {

layout/base/nsLayoutUtils.h

@@ -252,6 +252,15 @@ public:
     DoNotRepaint
   };
 
+  /**
+   * Invalidate for displayport change.
+   */
+  static void InvalidateForDisplayPortChange(nsIContent* aContent,
+                                             bool aHadDisplayPort,
+                                             const nsRect& aOldDisplayPort,
+                                             const nsRect& aNewDisplayPort,
+                                             RepaintMode aRepaintMode = RepaintMode::Repaint);
+
   /**
    * Set the display port margins for a content element to be used with a
    * display port base (see SetDisplayPortBase()).

layout/generic/nsGfxScrollFrame.cpp

@@ -3302,6 +3302,9 @@ ScrollFrameHelper::BuildDisplayList(nsDisplayListBuilder*   aBuilder,
     }
   }
 
+  // It's safe to get this value before the DecideScrollableLayer call below
+  // because that call cannot create a displayport for root scroll frames,
+  // and hence it cannot create an ignore scroll frame.
   bool ignoringThisScrollFrame =
     aBuilder->GetIgnoreScrollFrame() == mOuter || IsIgnoringViewportClipping();